If you want leather, there's going to be some sort of connection, because you probably don't want a leather dildo (too much effort to clean, amongst other things).

The huge advantage of a separate harness / dildo set up - usually using an O ring on the harness for the dildo to go through - is that you can have the same very good harness with a variety of size dildos.

Mine come from Babes n Horny and Sh! but if you want a 'one item' one, have a look at the Feeldoe. (Sh! do some clones of this which they can't export to the US for patent reasons...)

The big disadvantage of the otherwise interesting 'Vac u lock' system is that it ties you into one limited range for your dildos, rather than being able to use anything with a wide enough base.

The pictures on the maker's site could be a lot more informative, but it also looks they only do one basic design of harness too, rather than having 'one / two / four' strap options and a variety of materials.

Mine all came from stalls at Pride when the London one was good, and both Babes n Horny and Sh! would have bargains there. That's at least a decade ago, so yes, they do last for ages.